1. Field of the Invention
This invention relates to surgical sutures and suturing systems generally and, more particularly, to a single unit surgical fastener and system for repairing torn meniscus tissue and method therefor.
2. Description of the Prior Art
There are a number of different sutures and fasteners in use for repairing torn meniscus tissue, as well as a number of different systems for using such sutures and fasteners. The types of sutures and fasteners currently in use include ordinary surgical sutures, barbs, staples, H-shaped fasteners, and combination suture/fasteners.
Since the advent of arthroscopic surgical technology, sutures have been used in one or more of the four techniques that are currently in general clinical use: (a) open meniscal repair--involving exposure of the capsule through a longitudinal incision, preparation of the meniscal rim and capsula bed, and placement of vertically and/or horizontally oriented sutures across the tear; (b) arthroscopic inside-out repair--involving a small posterior incision carried down to the capsule for suture retrieval, the placement of sutures inside the knee arthroscopically, and the tying of sutures over the capsule; (c) arthroscopic outside-in repair--involving incisions made perpendicular to the joint line, the placement of a spinal needle across the tear from outside to inside the knee, the passing of sutures through the needle and into the joint, and the tying of the suture with multiple knots outside the knee followed by the pulling of these knotted sutures into the knee joint and the tying of the sutures outside the knee joint; and (d) arthroscopic all-inside repair--involving the piercing of both sides of the tear with a cannulated suture hook, the passing of the suture through the hook and across the tear, and the securing of the sutures using a knot pusher.
The indications for the four surgical techniques, and the relative risks and benefits of each, are varied. However, where possible, the all-inside technique is generally considered the most advantageous because it avoids the necessity for additional incisions beyond the initial incision and limits risk to the neurovascular bundle located in the posterior aspect of the knee.
Over the years, a number of fasteners have been developed to be used as alternatives to sutures. For example, U.S. Pat. No. 5,320,633 shows an H-shaped fastener that is delivered using a straight cannula, which cannula is guided into the meniscus using a guide pin. U.S. Pat. No. 4,873,976 shows an arrow-type surgical fastener for use in repairing meniscus tissue. U.S. Pat. No. 4,635,637 shows a twin-barbed fastener for use in repairing meniscus tissue. U.S. Pat. No. 5,562,704 shows a surgical implant having a plurality of cuts in the body to arrest the implant in position. There are relative advantages and disadvantages to these fasteners; however, none of these references shows a delivery system using a cannula that has been curved to conform to the concavity and convexity of the knee and to thus reduce the risk of injury to the neurovascular bundle in the posterior aspect of the knee. Moreover, these references do not disclose a method for effectively compressing the tear in the meniscus for purposes of accurately measuring the size of fastener needed--using the same cannula that is used to deliver the fastener and thus avoiding the need for additional incisions or insertions. The lack of an effective measuring system can lead to the obviously undesirable result of using a fastener of improper size in meniscus repair.
Hybrid suture/fasteners have also been developed as an alternative to simple sutures. U.S. Pat. Nos. 4,741,330 and 5,269,809 are examples of two such hybrid designs. However, the need to cut and tie off the sutures and to otherwise secure the suture/fastener in place makes these devices more complicated to use than single unit fasteners, and extends the amount of time required for the surgical repair of the meniscus.
Therefore, a need existed for a meniscus repair device and system allowing for relatively quick repair of torn meniscus tissue, with a minimum of incisions and thus preferably usable in an all-inside procedure. The improved device and system must also provide for accurate measurement of the desired fastener length--using the same instrument used to insert and position the fastener and without the need for an additional incision or the insertion into the knee of a second instrument. Finally, the improved device and system must reduce the risk of injury to the neurovascular bundle located in the posterior aspect of the knee. The single unit surgical fastener and system and method of the present invention provides these and other related advantages.